Persistent pupillary membrane

Persistent pupillary membrane (PPM), also known as persistent pupillary membrane, is a remnant of incomplete absorption of the vascular membrane on the surface of the lens during the embryonic period. During fetal development, the lens is surrounded by a vascular membrane, which completely absorbs and disappears by the 7th month of gestation. If this normal atrophy and absorption is abnormal, it will lead to the persistence of pupillary membrane. The persistent pupillary membrane itself is avascular, and its pigmentation usually develops secondarily after birth.